JP2013504054A - Method, system and apparatus for identifying the type of test strip - Google Patents

Abstract

In a method for determining the type of test strip in a glucose meter, (a) inserting the test strip into a strip port connector of the glucose meter having separate first, second and third contacts. And (b) determining whether there is continuity between the first contact and the second contact that are in electrical connection with at least one contact pad of the test strip; and (c) one of the test strips. Evaluating whether there is continuity between a third contact and a first contact in electrical connection with one or more contact pads or between a third contact and a second contact; (d ) Starting a glucose test based on detecting continuity in the determining and evaluating steps. A glucose meter comprising a strip connector having a first contact, a second contact and a third contact, the third contact being connected to ground, a source input, a drain input and a gate input A switch with the source input connected to ground and the drain input connected to the first contact, a first interrupt connected to the gate input of the switch, and a second interrupt connected to the second contact A glucose meter comprising: a microcontroller comprising: a microcontroller in electrical communication with the first contact and the third contact upon insertion of a test strip.
[Selection] Figure 10

Description

(Cross-reference of related applications)
This application claims the benefit of priority from US Provisional Application No. 61 / 240,133, filed September 4, 2009, under Sections 119 and 120 of the US Patent Act. This application is hereby incorporated by reference in its entirety.

  The determination of an analyte in a fluid sample (eg, detection, evaluation or calculation of numerical or concentration measurements) is of particular interest in the medical field. For example, it may be desirable to determine the concentration of glucose, cholesterol, acetaminophen and / or HbA1c in a sample of body fluid such as urine, blood, interstitial fluid. Such determination can be accomplished by using the analyte test strip with associated test instruments, for example, based on photometric or electrochemical techniques.

  A typical electrochemical-based analyte test strip uses multiple electrodes (eg, a working electrode and a reference electrode) and an enzyme reagent that promotes an electrochemical reaction with the analyte of interest, thereby This is for measuring the concentration of the specimen. For example, an electrochemical-based analyte test strip for measuring glucose concentration in a blood sample can use an enzyme reagent that includes the enzyme glucose oxidase and the mediator ferricyanide. Such conventional specimen test strips are described in, for example, Patent Document 1, Patent Document 2, Patent Document 3, and Patent Document 4, each of which is incorporated herein in its entirety. Measuring instruments that use electrochemical cells, such as typically provided by disposable test strips, are well known and popular with consumers. Such instruments are used for detecting various analyte levels in physiological fluid samples. For example, the concentration of the analyte in various physiological samples such as urine, tears, saliva, etc. can be determined by such a device. One common application is to determine the concentration of an analyte in interstitial fluid, blood or blood fractions, and more particularly whole blood.

US Pat. No. 5,708,247 US Pat. No. 5,951,836 US Pat. No. 6,241,862 US Pat. No. 6,284,125

  In one embodiment, a method is provided for determining the type of glucose meter test strip. The method includes the step of inserting a test strip into a strip port connector of a glucose meter having separate first, second and third contacts, and electrical connection with at least one contact pad of the test strip Determining whether there is electrical continuity between the first contact and the second contact, and a third contact and a first contact in electrical connection with one or more contact pads of the test strip A step of evaluating whether there is conduction between the contacts or between the third contact and the second contact, a step of determining, and a step of starting a glucose test based on detection of conduction in the evaluation step And can be achieved by.

  In yet another embodiment, a glucose meter is provided that includes a connector, a switch, and a microcontroller. The connector has a first contact, a second contact, and a third contact, and the third contact is connected to ground. The switch has a source input, a drain input, and a gate input, the source input is connected to ground, and the drain input is connected to the first contact of the connector. The microcontroller has a first interrupt connected to the gate input of the switch and a second interrupt connected to the second contact of the connector. The microcontroller is also in electrical communication with the first contact and the third contact upon insertion of the test strip.

  In yet another embodiment, a glucose measurement system is provided that includes a glucose test strip and a glucose meter. The glucose test strip has a plurality of conductive tracks. The glucose meter includes a power supply, ground, strip port connector, transistor switch, and microcontroller. The strip port connector has a first contact, a second contact, and a third contact having a plurality of conductive tracks, the third contact being connected to ground. The transistor switch has a source input connected to ground, a drain input connected to the first contact of the strip port connector, and a gate input. The microcontroller has a first interrupt connected to the gate input of the switch and a second interrupt connected to the second contact. The microcontroller is also in electrical communication with the first contact and the third contact upon insertion of the test strip.

  In yet another embodiment, a method is provided for distinguishing between a first type of analyte test strip and other analyte test strips by means of transistor switches and microcontrollers. The transistor switch has a gate input connected to the first interrupt of the microcontroller, a drain input of the switch connected to the first contact, and a source input of the switch connected to ground. The method inserts a test strip into the strip port connector so that the contact pads of the strip are in electrical connection with the first contact, the second contact, and the third contact; Detecting by interruption whether the first contact is connected to a second contact and a third contact formed by the configuration of one or more contact pads of the analyte test strip; A step of turning on and off the switch a predetermined number of times by a first interrupt based on detection of a common connection of the second contact and the third contact; a step of detecting a change in a logic state in the second interrupt; Identifying the glucose test strip as one of the first type or another type based on the number of high and low logic states of the two interrupts; It can be formed.

  These and other embodiments, features and advantages will become apparent to those of ordinary skill in the art by referring to the following more detailed description of embodiments of the invention, together with the accompanying drawings, which are briefly described below. I will.

  The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate preferred embodiments of the invention, and together with the general description set forth above and the detailed description set forth below. It serves to explain the features of the present invention.

Fig. 2 illustrates an analyte measurement and management device capable of identifying a specific type of test strip. The upper part of the typical circuit board of the sample measurement and management apparatus in the apparatus of FIG. The lower part of the circuit board of the sample measurement and management apparatus in the apparatus of FIG. FIG. 2 is a simplified exploded perspective view of a first type of test strip. FIG. 5 is a layer arrangement of the first type of test strip of FIG. 4. Arrangement of layers of the second type of test strip. A plurality of connector points corresponding to the contact pads of the first type of test strip of FIG. A plurality of connector points corresponding to the contact pads of the second type of test strip of FIG. Alternative test strip embodiments having various contact pad patterns. Alternative test strip embodiments having various contact pad patterns. Alternative test strip embodiments having various contact pad patterns. Alternative test strip embodiments having various contact pad patterns. Alternative test strip embodiments having various contact pad patterns. Alternative test strip embodiments having various contact pad patterns. Alternative test strip embodiments having various contact pad patterns. An electronic circuit for identifying a first type of test strip having a particular pattern of contact pads. The electronic circuit of FIG. 10 for identifying a second type of test strip having a specific pattern of contact pads. Strip discriminating line for controlling the switch to check the identification of the type of test strip. A strip detect line that monitors the high and low logic states over time as a result of the toggle of the switch by the first type of test strip. A strip detect line that monitors the high and low logic states over time as a result of the toggle of the switch by the second type of test strip. A strip detect line that monitors the high and low logic states over time as a result of the toggle of the switch with the inserted, removed, and reinserted test strip. 6 is a flowchart illustrating the most detailed logic for recognizing test strip insertion and then identifying the type of test strip. 5 is a flowchart illustrating in more detail the process of determining the type of test strip. 5 is a flowchart illustrating in more detail a process for attempting to determine the type of test strip.

  The following detailed description should be read with reference to the drawings, in which like elements in different drawings are designated with like reference numerals. The drawings are not necessarily to scale and illustrate certain exemplary embodiments and are not intended to limit the scope of the invention. The detailed description is not intended to limit the principles of the invention but is provided as an example only. This description clearly makes it possible for those skilled in the art to make and use the invention, and includes a plurality of embodiments and application examples of the invention, including what is considered the best mode for carrying out the invention at the time of filing , Variations, alternatives, and usage examples are described.

  The term “about” or “approximately” as used herein for any numerical value or range of numerical values allows a component part or set of components to function according to its desired purpose as described herein. The tolerance of an appropriate dimension is shown. Further, as used herein, the terms “patient”, “host”, “user”, and “subject” refer to any human or animal subject and are intended to limit the system or method to human use. Although not intended, the use of the present invention in human patients represents a preferred embodiment.

  FIG. 1 illustrates a diabetes management system that includes a blood glucose measurement device 100 with a blood glucose test strip 120 having an inlet 122 for receiving a blood sample. The blood glucose measurement device 100 includes a housing 102 having a test strip port 104 configured to receive a test strip, together with user interface buttons 108, 110, and 112, and a display 106. As shown in FIG. 2, disposed within the housing 102 is a circuit board 200 having a memory 204, a clock 206, an operational amplifier 208, and a microcontroller 202 connected to the display connector 210. The operational amplifier 208 and microcontroller 202 are contacts 212a, 212b, 212c, 212d and 212e (first, second, third, fourth, or respectively, respectively) for mechanical contact with corresponding contact pads on the test strip 120. 5), the strip port connector 212 is operatively connected. To facilitate communication with other data management devices, a wireless transceiver module 214 is provided to allow bidirectional communication of data stored in the memory 204 of the unit 100. As shown in FIG. 3 of the present specification, a power source in the form of a battery 215 is provided on the opposite side of the circuit board 200. A data port 218 may be provided. Device 100 is preferably sized and shaped to be handheld, and transceiver 214 may be a short range wireless network (eg, such as BlueTooth®, Zigbee®, or Wi-Fi) or Note that it may be for use in either or both of longer distance wireless networks (eg, GSM®, CDMA, 3G, etc.).

  Referring back to FIG. 2, the microcontroller 202 includes a strip port connector 212, an operational amplifier circuit 208, a first wireless module 214, a display 106, a non-volatile memory 204, a clock 206, a battery connector 216, a data port 218, and a user interface. It may be electrically connected to the buttons (108, 110 and 112). Specifically, the user interface buttons (108, 110 and 112) include a first user interface button 108, a second user interface button 110, and a third user interface 112. The input data may include a value representing the analyte concentration (that is, an analyte concentration value with information related to an individual's daily lifestyle). Information related to daily living habits is combined with the user's sample concentration value at a specific time of day or week, ie “in addition to” this, personal food intake, drug use, health check As well as general health and exercise levels.

  The operational amplifier circuit 208 may be two or more operational amplifiers configured to provide part of the potentiostat function and the current measurement function. The potentiostat function may refer to applying a test voltage between at least two electrodes of the test strip. Current function may refer to the measurement of test current due to the test voltage applied to test strip 120. The current measurement can be performed by a current-voltage converter. The microcontroller 202 may be in the form of a mixed signal microprocessor (MSP), such as, for example, a Texas Instrument MSP430F2419. The TI-MSP430F2419 may also be configured to perform some of the potentiostat function and the current measurement function. In addition, MSP430F2419 may include volatile and non-volatile memory. In another embodiment, many of the electronic components may be integrated with a microcontroller in the form of an application specific integrated circuit (ASIC).

  Referring again to FIG. 2, the strip port connector 212 may be configured to form an electrical connection to the test strip. Display connector 210 may be configured to attach to display 106. The display 106 is a liquid crystal display for reporting measured blood glucose levels, facilitating input of information associated with lifestyle habits, and manipulating graphic data, graphical results and animation, as shown in FIG. It may be a form. Display 106 may include a backlight.

  Referring to FIG. 3, the data port 218 can accept a suitable connector attached to a connection lead, thereby allowing the measurement device 100 to be coupled to an external device such as a personal computer. The data port 218 may be any port that allows data transmission, such as a serial, USB, or parallel port. The clock 206 may be configured to measure time and may be in the form of a vibrating crystal. The battery connector 216 can be configured to be electrically connected to the battery 215.

  With the measurement device 100, an exemplary test strip 120 as shown in FIG. 4 is used, which includes the electrically insulating substrate 12, the patterned conductive layer 14 disposed on the electrically insulating substrate 12, the patterned Patterned insulating layer 16 disposed on conductive layer 14, enzyme reagent layer 18 disposed at least on at least a portion of patterned conductive layer 14, pattern disposed on at least a portion of patterned insulating layer 16 An adhesive layer 20, a hydrophilic layer 22 disposed on the patterned adhesive layer 20, and an upper layer 24 disposed on the hydrophilic layer 22 having two portions 22a and 22b (which is opaque to the first portion 24a). Second portion 24b). As shown in FIGS. 5 and 6, the patterned adhesive layer 20 may include three pads (20a, 20b and 20c).

  FIG. 5 shows an arrangement of layers of the first type test strip 120 of FIG. The type of test strip may refer to a specific trademark of the test strip that is configured to perform a glucose test on the blood glucose monitor 100. In one embodiment, blood glucose monitor 100 may be configured to perform a glucose test only on the first type of test strip (120). The patterned conductive layer 14 can include a reference electrode 14a, a first working electrode 14b, a second working electrode 14c, a reference contact pad 15a, a first contact pad 15b, and a second contact pad 15c. In one embodiment, the contact pads may be referred to as conductive tracks. As shown in FIGS. 4 and 5, the reference electrode 14a, the first working electrode 14b, and the second working electrode 14c are respectively a reference contact pad 15a, a first contact pad 15b, and a second contact pad 15c. Are electrically connected to each other. Note that the contact pad arrangement and geometry may indicate a particular trademark or type of test strip. In one embodiment, the contact pads (15a, 15b and 15c) may be configured to electrically interact with corresponding contacts on the strip port connector.

  Referring back to FIGS. 4 and 5, the electrically insulating substrate 12 of the electrochemical analytical test strip 120, the patterned conductor layer 14 (including the reference electrode 14a, the first working electrode 14b, and the second working electrode 14c). The patterning arrangement and alignment of the patterned insulating layer 16 (with the electrode exposure window 17 extending) and the enzyme reagent layer 18 and the patterned adhesive layer 20, hydrophilic layer 22, and upper layer 24 are It is such that a sample receiving chamber is formed in the chemical analysis test strip 120.

  The electrochemical analysis test strip 120 includes, for example, a patterned conductor layer 14, a patterned insulating layer 16 (in which an electrode exposure window 17 extends), an enzyme reagent layer 18, and a patterned pattern on the electrically insulating substrate 12. The adhesive layer 20, the hydrophilic layer 22 and the upper film 24 may be manufactured by continuous alignment formation. Any suitable technique can be used to achieve such continuous alignment formation, including, for example, screen printing, photolithography, gravure printing, chemical vapor deposition and tape lamination techniques.

  In using the electrochemical analytical test strip 120 to determine the analyte concentration in a fluid sample (eg, the blood glucose concentration of a whole blood sample), the electrodes 14a, 14b and 14c of the patterned conductor layer 14 cause an electrochemical reaction. Used to monitor the current of interest induced by. Such current magnitude can then be related to the amount of analyte present in the fluid sample under investigation. In such use, a body fluid sample is introduced into the sample receiving chamber 26 of the electrochemical analytical test strip 10.

  FIG. 6 shows the layer arrangement of the second type of test strip 124. The test strip 124 may be similar to the test strip 120, with the test strip 124 having a different patterned conductive layer 54 and a different patterned insulating layer 56 having an electrode exposure window 57. In one embodiment, blood glucose monitor 100 may be configured not to perform a glucose test on second type test strip 124. In another embodiment, blood glucose monitor 100 may be configured to perform a glucose test with either a first type or second type test strip.

  Referring again to FIG. 6, the patterned conductive layer 54 includes a reference electrode 54a, a first working electrode 54b, a second working electrode 54c, a reference contact pad 55a, a first contact pad 55b, and a second contact pad. 55c may be included. As shown in FIG. 6, the reference electrode 54a, the first working electrode 54b, and the second working electrode 54c are respectively connected to the reference contact pad 55a, the first contact pad 55b, and the second contact pad 55c. Electrically connected. In one embodiment, the contact pads (15a, 15b and 15c) may be configured to electrically interact with corresponding contacts on the strip port connector.

  The electrically insulating substrate 12 is common to both the first type strip 120 and the second type strip 124, and is a nylon substrate, polycarbonate substrate, polyimide substrate, polyvinyl chloride substrate, polyethylene substrate, polypropylene substrate, It can be a glycol-modified polyester (PETG) substrate or a polyester substrate. The electrically insulating substrate can have any suitable dimension, such as a width dimension of about 5 mm, a length dimension of about 27 mm, and a thickness dimension of about 0.5 mm.

  The electrically insulating substrate 12 provides the strip with an easy-to-handle structure and serves as a foundation for applying (eg, printing) subsequent layers (eg, carbon-based patterned conductive layers). Note that the patterned conductor layer used in the analytical test strip can take any suitable shape and can be formed from any suitable material, such as, for example, metallic materials and conductive carbon materials.

  The patterned conductive layer 14 includes a counter electrode 14a (also referred to as a reference electrode), a first working electrode 14b, and a second working electrode 14c (see FIGS. 4 and 5). Although test strip 120 is depicted as including three electrodes, embodiments of electrochemical analysis test strips may include any suitable number of electrodes.

  The counter electrode 14a, the first working electrode 14b, and the second working electrode 14c are formed from any suitable material such as, for example, gold, palladium, platinum, indium, titanium palladium alloy, and a conductive carbon-based material. May be. Details regarding the use of electrodes and enzyme reagent layers to determine the concentration of an analyte in a fluid sample are in US Pat. No. 6,733,655, which is hereby incorporated by reference in its entirety.

  The patterned insulating layer 16 may be formed of an insulating ink that can be screen-printed, for example. Such a screen-printable insulating ink is commercially available from Ercon (Wareham, Massachusetts USA) under the trade name “Insulayer”.

  The patterned adhesive layer 20 may be common to both the strip 120 and the strip 124 and may be formed of, for example, a screen-printable pressure sensitive adhesive commercially available from Apollo Adhesives (Tamworth, Staffire, UK). In the embodiment of FIGS. 4 and 5, the patterned adhesive layer 20 defines the outer wall of the sample receiving chamber 26.

  The hydrophilic layer 22 may be common to both the strip 120 and the strip 124 and has hydrophilic properties that facilitate wetting and filling of the electrochemical analytical test strip 120 with, for example, a fluid sample (eg, a whole blood sample). It can be a transparent film. Such a transparent film is commercially available, for example, from 3M (Minneapolis, Minnesota USA).

  Enzyme reagent layer 18 may be common to both strip 120 and strip 124 and may include any suitable enzyme reagent, the choice of enzyme reagent depending on the analyte to be determined. In one embodiment, two overlapping enzyme reagent layers 18 such as a first reagent layer 18a and a second reagent layer 18b may be printed on the conductive layer shown in FIG. For example, when determining glucose in a blood sample, the enzyme reagent layer 18 may include enzymes and mediators along with other components necessary for functional operation. The enzyme reagent layer 18 can include, for example, glucose oxidase, sodium tricitrate, polyvinyl alcohol, hydroxylethyl cellulose, potassium ferricyanide, antifoaming agent, cabosil, PVPVA, and water.

  Exemplary enzymes suitable for use in the reagent layer include glucose oxidase, glucose dehydrogenase (with pyrroloquinoline quinone cofactor “PQQ”), and glucose dehydrogenase (with flavin adenine dinucleotide cofactor “FAD”). It is done. An exemplary vehicle suitable for use in the reagent layer is ferricyanide, in this case the oxidized form. The reagent layer may be configured to physically convert glucose into an enzyme byproduct and produce in the process an amount of reduction mediator (eg, ferrocyanide) proportional to the glucose concentration value. Further details on enzyme reagent layers and electrochemical analytical test strips in general are described in US Pat. No. 6,241,862, the contents of which are hereby incorporated by reference in their entirety.

  The upper layer 24 may be common to both the strip 120 and the strip 124 and includes a first portion 24a (eg, a transparent or translucent first portion) and an opaque second portion 24b. The upper first portion 24a and the opaque second portion 24b allow the user to see the working portion of the sample receiving chamber through the upper first portion, but the upper layer opaque second portion allows sample reception. The non-working part of the chamber is configured so that it cannot be seen and is aligned with the rest of the analytical test strip. This arrangement prevents the user from erroneously determining that a sample fill error has occurred when the working portion of the sample receiving chamber is filled but the non-working portion is not filled.

  The upper layer 24 may be, for example, a transparent film, in which the opaque second portion 24b is made by overlaying opaque ink on the transparent film, and the first portion 24a is a simple transparent film that does not overprint. It may be. Suitable transparent films are commercially available from Tape Specialties UK.

  7 and 8 illustrate a plurality of strip port connector points that are designated areas on the contact pads of the first and second types of test strips. The strip connector points may be referred to as p4, ref, w2, w1, and p5. Contacts 212d, 212a, 212b, 212c and 212e of strip port connector 212 are in electrical contact with contact pads at strip connector points p4, ref, w2, w1 and p5, respectively, when the test strip is inserted into the blood glucose meter. be able to. The embodiments described herein should not be limited to those described in FIGS. 7 and 8, but applied to various contact pad patterns shown in FIG. 9 and referred to as patterns A-L. Please note that

  Applicants have recognized that there is a need for a blood glucose meter that can distinguish between different types of test strips. The blood glucose meter may be configured to perform a glucose test with a particular type of test strip, and if a different type of test strip is inserted, the meter can output an error message. The method for determining the type of test strip must be robust so that no false positives are caused by inadvertent withdrawal of the test strip or the introduction of noise.

  In one embodiment, electronic circuitry may be used to distinguish between different types of test strips. FIG. 10 shows an electronic circuit 300 for identifying the first type of test strip 120, which may be integrated on the circuit board 200. The electronic circuit 300 can include a pull-up resistor 302, a capacitor 308, a switch 304 and a microcontroller 306. The pull-up resistor 302 is connected to the power supply voltage Vcc and limits the amount of current flowing through the electronic circuit when the strip is inserted into the blood glucose meter 100. Capacitor 308 is connected to the electronic circuit to filter the measured voltage.

  The switch 304 can be in the form of a metal oxide semiconductor field effect transistor (eg, MOSFET or FET). The microcontroller 306 can control a switch 304 for measuring a signal obtained by applying a voltage waveform. More specifically, the microcontroller 306 opens and closes the transistor switch 304 at the first interrupt and measures the transition in the logic state at the second interrupt, so that the glucose meter 100 can detect the first or second. Two types of test strips 120 or 124 may be configured to be identified, respectively. The transistor switch has a source input 310 connected to ground, a drain input 312 connected to connector point p4, and a gate input 314 connected to the first interrupt of the microcontroller along the strip discriminant line (S_DISC). You may have.

  The electronic circuit 300 may be electrically connected to the contacts (212d, 212a, 212b, 212c and 212e) of the strip port connector 212, which are respectively connected to the connector points (p4, ref, w2, w1 and p5). Connected. The strip detect line (S_DET) may be a second interrupt for connector point p5 and from microcontroller 306. The strip discriminant line (S_DISC) may be the first interrupt to the switch 304. Switch 304 may be connected to reference connector point p4, microcontroller 306, and ground. The reference connector point ref may be connected to ground.

  Referring again to FIG. 10, switch 304 is initially closed while the meter is in sleep mode and the strip has not yet been inserted. At this point, the gate point A in the figure is driven high. Points B and C are also shorted and are therefore connected to ground. Since connector points p4 and p5 are discontinuous, contact point D remains high, which is limited by pull-up resistor 302 and power supply voltage Vcc.

  When the first type of test strip 120 is inserted into the strip port connector 212, the connector points ref, p4 and p5 are shorted together, as shown in FIG. Therefore, since connector points p4 and p5 are short-circuited, insertion of strip 120 pulls point D from the power supply voltage Vcc level to ground. A change in the state of the S_DET pin of microcontroller 306 alerts the instrument to turn on. Microcontroller 306 then toggles the gate to FET switch 304 at point A to High and Low for several pulses (preferably about 4 pulses). The toggle of switch 304 has the effect of opening and closing the conduction between points B and C.

  In the situation where the first type of test strip 120 is inserted, point D is always held at logic low (ie, GND), and at the same time the switch is connected to ref via p4, and ref is connected to GND. It is opened and closed four times. After the pulse is applied, the microcontroller 306 attempts to determine if there is continuous low level logic to ensure that the test strip has not been removed during the strip identification process. If the microcontroller 306 detects continuous low level logic during the pulse and for a period thereafter, the software recognizes the presence of the first type of test strip 120 and performs a blood glucose test by prompting the user to apply blood. Start.

  FIG. 12A shows the strip discriminant line for controlling the switch 304 to check the type of test strip type. Initially, when the strip 120 is not connected to the meter 100, the strip discriminant line logic remains High. At some point after the strip is inserted and recognized, p4 and p5 are shorted and the logic toggles between High and Low. In the embodiment shown in FIG. 12A, there are 4 High and 3 Low, but other numbers of High and Low may be used to reliably identify the type of test strip. In another embodiment, four highs and four lows may be used, each high pulse and low pulse having a duration of about 30 milliseconds. In a preferred embodiment, the generated strip discrimination pulse is sent for a duration greater than about 2 seconds after the meter detects the strip insertion and completes its self-test.

  The frequency of the pulse must be high enough that it cannot be reproduced by a manual insertion and removal process by the user. The user may insert and remove the strip approximately 10 times / second (ie, 100 milliseconds / cycle). Thus, in one embodiment, the pulse length may be less than 50 milliseconds so that the pulse length is about one-half shorter than the manual process. In an alternative embodiment, the pulse waveform may be asymmetric, in which case the Low pulse may be about 20 milliseconds and the High pulse may be about 5 milliseconds.

  FIG. 12B shows a strip detect line that monitors the high and low logic states over time as a result of the toggle of the switch by the first type of test strip. When the first type of test strip 120 is inserted, the strip detection line transitions from High to Low. Even when the strip discriminating line toggles between High and Low, the strip detection line remains Low. At some time after the toggle of the switch, the microcontroller starts the glucose measurement process after confirming that the strip 120 has not been removed. In one embodiment, a debounce timer is disabled at the start of the discriminant test. The debounce timer may be any hardware or software utilized to ensure that the signal is read correctly upon contact between the contact pad and the strip port connector contact. Confirmation that the strip has not been removed is accomplished by re-enabling the strip detect interrupt and monitoring the low logic state for approximately 200 milliseconds, which is approximately the duration of the debounce timer.

  FIG. 11 shows an electronic circuit 300 for identifying a second type of test strip 124. Initially, switch 304 is closed while the instrument is in sleep mode and no strip is inserted. At this point, gate point A in the figure is driven high. Points B and C are also shorted and are therefore connected to ground. Since connector points p4 and p5 are discontinuous, point D remains High, which is limited by pull-up resistor 302 and power supply voltage VCC.

  When the second type test strip 124 is inserted into a strip port connector configured specifically for the first type strip 120, the connector points p4 and p5 are shorted together as shown in FIG. Thus, since connectors p4 and p5 are shorted together, the insertion of the second type of strip 124 pulls point D down from the VCC level to GND. A change in the state of the S_DET pin of the microcontroller 306 alerts the instrument to activate because the strip has been inserted. When strip insertion is detected, the microcontroller 306 then toggles the gate to the point A FET switch 304 high and low for a total of four pulses. The toggle of switch 304 has the effect of opening and closing the conduction between points B and C.

  In situations where a second type of test strip 124 (instead of the first type of strip 120) has been inserted, the S_DET pin reads back four pulses. The logic level transitions to high when the switch 304 is open and transitions to low when the switch 304 is closed. In contrast to the insertion of the first type of test strip 120, point D is not always held at logic low (ie, GND) because there is a non-continuous connection between p4 and ref. Please note that. The microcontroller determines whether the S_DET pin measures the same number of pulses (eg, 4 pulses) sent by the S_DISC pin. If this condition is true, the microcontroller 306 may determine that a second type of test strip 124 has been inserted and output an error message, which may be an audio, video or audio signal from the meter 100. It may be due to both video notifications. However, if the S_DET pin measures a different number of pulses than that sent by the S_DISC pin, the process of sending four pulses to detect the presence of the second type of test strip 124 is performed two more times. Repeated.

  FIG. 13 shows a strip detect line that monitors the high and low logic states over time as a result of the toggle of the switch by the second type of test strip 124. When the second type of test strip 120 is inserted, the strip detection line transitions from High to Low. However, when the strip discrimination line transitions from High to Low, the strip detection line transitions from Low to High, and vice versa. At some time after the toggle of the switch, the microcontroller 306 starts the glucose measurement process after confirming that the strip 120 has not been removed.

  Under certain circumstances, due to test strip removal and reinsertion and environmental noise, the S_DET pin may measure a different number of pulses than the pulse sent by the S_DISC pin. FIG. 14 shows a strip detect line that monitors the high and low logic states over time as a result of the toggle of the switch due to the inserted, removed, and reinserted test strips. When the test strip is removed during the pulsing process, the number of High and Low seen on the strip detect line S_DET is different from the strip discriminant line S_DISC. When this happens, the process of sending the appropriate waveform, eg a square wave, is repeated two more times to see if the test strip type can be identified.

  FIG. 15 is a flowchart illustrating the most detailed logic 1500 for recognizing test strip insertion and then identifying the type of test strip. If a test strip insertion is detected with a strip detection interrupt, the interrupt is disabled, as shown in step 1502. The strip detection interrupt is disabled before the decision attempt (see subroutine 1700 of FIG. 17), and the pending interrupt is cleared after the decision attempt and before the interrupt is re-enabled. This is because the interrupt is flagged as pending due to the operation of pulsing the strip detect line, and if the pending interrupt is not cleared, this causes the debounce logic to operate wastefully. A pending interrupt may refer to an interrupt that has been registered but not yet done. Note that if the interrupt is re-enabled when there is a pending flag, this invokes the interrupt service routine, which starts the debounce logic.

  As shown in FIG. 16, after step 1502, a subroutine 1600 is executed. As shown in steps 1506 and 1508, any pending flag for the strip detection interrupt is cleared and then the strip detection interrupt is enabled. For example, a microprocessor such as MSP 430 has an “IFG” register that latches edge transitions detected at the strip detect input. Regardless of whether the interrupt is enabled or disabled, the microprocessor can set this register to indicate a “pending flag” at its input. Next, as shown in step 1510, whether a first type of strip has been identified, a second type of strip has been identified, a strip has not been successfully identified, or a strip has been prematurely removed. Determined. As shown in step 1516, if a first type of strip is identified, the blood glucose meter can display a blood application prompt. If a second type of strip is identified, a “strip failure” timer may be started, as shown at step 1518. If the strip was not successfully identified, or if the strip was removed prematurely, the strip detect interrupt pending flag is set, as shown in steps 1512, 1514 and 1518, the strip debounce timer and "strip bad" Both timers can be started.

  In both scenarios where the strip is not identified but determined to be present and when it is determined that the strip is not present, the strip removal bounce timer is started and "strip bad" immediately after the debounce time expires. Note that the timer is set to start. If this “bad strip” timer event is received, as shown in step 1520, an error message is displayed. As shown in step 1522, if the debounce timer expires (occurs before the "Strip Bad" timer event if the strip was not reinserted) and strip removal is detected, a normal strip removal event is Generated and processed, after which an error message is displayed. If it is determined that a strip is present when the debounce timer expires, a strip removal event is not generated and an error message is displayed when a "strip bad" timer event is received. This prevents temporary display of error messages when the strip is removed during the strip type detection operation.

  FIG. 16 is a flowchart illustrating in more detail the process of determining the type of test strip using subroutine 1600. As shown in step 1602, initially, attempt_count is set to zero. Next, as shown in step 1700, a determination attempt subroutine is executed. As shown in step 1604, after subroutine 1700, it is determined whether the determination was successful or whether the determination was not deterministic. If the determination is not deterministic, attempt_count is incremented by 1, as shown in step 1606. At step 1608, attempt_count is compared to threshold 3. If attempt_count is less than 3, steps 1700, 1604 and 1606 are repeated. As shown in step 1610, if attempt_count is 3, the determination fails.

  FIG. 17 is a flowchart showing in more detail the process of trying to determine the type of test strip. As shown in steps 1702, 1704, 1706, and 1708, first, pulse_count, low_count, and high_count are all set to 0, and the discrimination line is set to Low. Next, as shown in step 1710, there is a waiting time of strip_type_detect_transient_delay (unit: millisecond). In one embodiment, strip_type_detect_transient_delay may be the amount of time that elapses before performing the read process, such as about 30 milliseconds. The delay time must be long enough to allow the input pin to reach logic high. As shown in step 1712, after step 1710, the microcontroller reads the strip detect line. As shown in step 1714, it is determined whether the strip detection line is high or low. If strip detection is high, high_count is incremented by 1 as shown in step 1716. However, if the strip detection is Low, the discrimination line is set to High as shown in Step 1718.

  Next, as shown in step 1720, there is a wait time of strip_type_detect_transient_delay (in milliseconds). After step 1720, as shown in step 1722, the microcontroller reads the strip detect line. As shown in step 1724, it is determined whether the strip detection line is high or low. If strip detection is low, low_count is incremented by 1 as shown in step 1726. However, if strip detection is high, pulse_count is incremented by 1, as shown in step 1728.

  After step 1728, it is determined whether pulse_count is equal to 4, as shown in step 1730. If pulse_count is less than a predetermined number (eg, preferably 4), the process returns to step 1708. However, if pulse_count is equal to a predetermined number (eg, preferably 4), the number of high_count increments and low_count increments are determined, as shown in step 1732. If high_count is equal to 4 and low_count is equal to 0, the strip has been removed, as shown in step 1740. If high_count is equal to 0 and low_count is equal to 4, the strip is of the first type, as shown in step 1738. If high_count is equal to 4 and low_count is equal to 4, the strip is of the second type, as shown in step 1734. If high_count and low_count are equal to any other combination not listed in steps 1734, 1738 and 1740, the strip type is not determined, as shown in step 1736.

  Any implementation of the processes of FIGS. 15-17 can mitigate the risk of the watchdog timer ending during the worst case scenario where three distinct attempts are made. This can be done by simply starting the watchdog timer. Note that the hardware watchdog timer is running during the strip type identification process. Thus, if finished during the strip type identification process, the processor will reset. Note that the strip discriminant line is assumed to be high at the start of the detection algorithm and back to the same “High” state at the end.

  While preferred embodiments of the present invention have been illustrated and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. For example, the invention may be applied not only to docking stations and glucose meters, but also to any electronic device that requires a power source and can be reset, such as an insulin infusion pump or continuous glucose monitoring system. it can. Furthermore, although various embodiments have been described regarding blood glucose as a specimen, other specimens such as ketones and cholesterols can be used. Many variations, modifications and alternatives will occur to those skilled in the art without departing from the invention. In practicing the invention, various alternatives may be used in the embodiments of the invention described herein. It is intended that the following “claims” define the scope of the invention and that the methods and structures of these “claims” and their equivalents be included therein.

Claims (13)

In a method for determining the type of test strip in a glucose meter,
(A) inserting a test strip into the strip port connector of the glucose meter having separate first, second and third contacts;
(B) determining whether there is electrical continuity between a first contact and a second contact in electrical connection with at least one contact pad of the test strip;
(C) whether there is continuity between a third contact and a first contact in electrical connection with one or more contact pads of the test strip or between the third contact and the second contact A process of evaluating
(D) starting a glucose test based on detection of conduction in the determining step and the evaluating step;
Including a method.   Providing an error message that a first type of test strip is not coupled to the glucose meter if continuity is detected in the determining step but not in the evaluating step. The method of claim 1 comprising.   Instructing the user to enter a calibration code when a second type of test strip is inserted into the glucose meter and continuity is detected in the determining step but not in the evaluating step. The method of claim 1, further comprising: (E) executing the determination step and the evaluation step at least once each;
(F) identifying that a first type of test strip is inserted when continuity is detected in the determining and evaluating steps;
The method of claim 1, further comprising:   The method of claim 1, wherein the first type of test strip has continuous conductive tracks in electrical communication with the first contact, the second contact, and a third contact.   The second type test strip has continuous conductive tracks that are in conduction with the first and second contacts but not with the third contact. Method.   4. A method according to claim 1, 2 or 3, wherein two of the three contacts are electrically connected to ground. A glucose meter,
A strip connector having a first contact, a second contact, and a third contact, wherein the third contact is connected to ground;
A switch having a source input, a drain input, and a gate input, the source input connected to ground, and the drain input connected to the first contact;
A microcontroller having a first interrupt connected to the gate input of the switch and a second interrupt connected to the second contact, wherein the first contact and the second interrupt when inserting a test strip A microcontroller in electrical communication with the three contacts;
A glucose meter.   9. The glucose meter of claim 8, wherein the second interrupt includes a connection to a power supply voltage via a pull-up resistor.   The glucose meter according to claim 8, wherein the switch includes one of a MOSFET and a FET switch.   The glucose meter of claim 8, wherein two of the three contacts are electrically connected to ground. In the glucose measurement system,
A glucose test strip having a plurality of conductive tracks;
A glucose meter,
Power and ground,
A strip port connector having first, second and third contacts, wherein the third contact is connected to ground;
A transistor switch having a source input connected to the ground, a drain input connected to a first contact of the strip port connector, and a gate input;
A microcontroller having a first interrupt connected to the gate input of the switch and a second interrupt connected to the second contact, wherein the first contact is upon insertion of the test strip. And a glucose meter in electrical communication with the third contact;
A glucose measurement system. In a method for distinguishing between a first type of analyte test strip and another analyte test strip by means of a transistor switch, the transistor switch is connected to a first input of a microcontroller and to a first contact. A drain input of the switch, and a source input of the switch connected to ground,
Inserting a test strip into a strip port connector so that the contact pads of the strip are in electrical connection with the first contact, the second contact and the third contact;
Whether the second interrupt of the microcontroller connected the first contact to the second contact and the third contact formed by the configuration of one or more contact pads of the analyte test strip Detecting
Turning the switch on and off a predetermined number of times by the first interrupt based on detection of a common connection of the first contact, the second contact, and the third contact;
Detecting a change in the logic state of the second interrupt;
Identifying a glucose strip as one of the first type or another type based on the number of high and low logic states of the second interrupt;
Including a method.

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